2 answers

Thanks for bringing this up. We're currently investigating a bug with the newer builds of SourceTree, specifically those with Mercurial installed and using Git Credentials Manager. Please follow along here: https://jira.atlassian.com/browse/SRCTREEWIN-7116

3- Do you have multiple repos hosted on the same server/service? / Do they all share the same credentials?

If you are using Windows Credentials Manager, can you open it and under the Windows Credentials check for any entries keyed with the “hg:” prefix. Does it look like the credentials you are entering are stored there?